Field of the Invention
The invention generally relates to electrolysis and to processes, compositions used therein, and method of preparing the compositions. More specifically, the invention relates to product, process, and electrolyte composition for electrolytic material treatment, where the material is water, sewage, or other waste water. In another aspect, the invention generally relates to the chemistry of electrical and wave energy. More specifically, the invention relates to electrolytic apparatus and to cells with electrolyte treatment means.
Description of Related Art
Electrocoagulation is a process of electrical destabilization of particles in water and is used to treat water to remove impurities. This process changes the surface charge of suspended particles, which allows suspended matter to form an agglomeration. Electrocoagulation is known to require no filters, no daily maintenance, and no additives. It is capable of removing any size of suspended solids, oil, grease and heavy metals.
Electrocoagulation employs processing chambers that may contain one or more electrolytic cells. A housing typically defines a single chamber and contains one or more cells. Where a chamber is formed of multiple cells, each cell performs electrolysis according to its own characteristics. A single cell is formed of at least two electrodes in contact with an electrolyte solution. The electrodes are made of metal or carbon. An electrical charge is applied across a pair of electrode plates to cause a flow of ions within the electrolyte solution, resulting in redox reactions at the electrodes. According to conventional terminology, one electrode of an electrode pair is an anode, where oxidation occurs. The second electrode of the electrode pair is a cathode, where reduction occurs. In an electrolytic cell, the anode is positively charged and the cathode is negatively charged. The oppositely charged plates produce ions that move in the electrolyte. Positive ions move toward the negative electrode and negative ions move toward the positive electrode.
An electrolytic cell is useful to decompose compounds in the electrolyte using electrical energy. For example, water in the electrolyte can be decomposed into hydrogen gas and oxygen gas. The practice of electrolysis upon aqueous solution containing other compounds can result in production of water plus an agglomerate. The latter can be separated from the water to produce residual clean water. This process and its chemistry are well known, and many types of apparatus are used in the practice of it.
While electrolysis is highly effective in producing clean water, attempts to operate an electrolytic cell on a continuous, long term basis with a complex or variable electrolyte stream have encountered maintenance and operational difficulties. One of these limitations is with current flow paths. In an idealized, text book model of a cell, oppositely charged plates face each other across a gap filled with water, and the major facing surfaces of the plates generate ions or other charged particles in the water. In practice, plate wear can be much more accelerated than suggested by the model cell. Electrical current tends to travel along selected pathways of least resistance and often concentrates at specific areas of an electrode, such as the edges of the electrode. Concentrated current flow is undesirable because it quickly erodes the areas where it travels. Current can cut channels through a plate, erode away a plate from one edge, and even cut off a connection tab that is supplying power to the plate. In some chambers, the plates have been selectively eroded to the point of premature collapse. These problems result in interruption of water treatment and may require extensive and frequent maintenance of the electrocoagulation chamber.
Electrocoagulation is effective for removing heavy metals, suspended solids, emulsified organics and many other contaminants from water. The contaminants are combined in a waste stream that produces floc, which is mainly insoluble oxides and hydroxides. A floc stream tends to settle for easy separation from the clear water.
It would be desirable for an electrocoagulation chamber to be quickly and easily serviced when maintenance is needed. An aspect of maintenance is the ability to quickly and easily reconfigure a cell to meet new operational requirements. Thus, an object of the invention is to simplify cell reconstruction and reconfiguration by use of a modular cell design.
Rebuilding a typical chamber involves the cost of new plates in addition to loss of use of the chamber during down-time. Electrode plates often are arranged within a housing by use of a spacer, which can be a slotted edge guide. The slots receive the plates, while intermediate portions of the guide between slots serve as spacers that establish a predetermined gap between plates. Typically, two guides establish the plate spacing parameters of the cell, with the two guides arranged on opposite sides of the plates or on top and bottom of the plates. Repairing almost any problem with a typical cell requires at least partial disassembly of the chamber.
Changing operational characteristics of a typical cell also requires at least partial disassembly of the chamber. For example, when treating certain electrolytes in a typical chamber, it may be necessary to change the plate gap that is currently established in a chamber. Typically, a change of plate gap is accomplished by switching the slotted guide for another with a more suitable intermediate dimension between slots. In addition, the accompanying loss of service time due to disassembly of a cell for any reason is undesirable.
Rebuilding or reconfiguring a cell often is a difficult process. Simply stating that there is a requirement to change a plate or change a guide is deceptively simple. In practice, a cell needing maintenance can be so clogged or corroded that removing a single plate or removing a single guide is ponderous work. Such simply stated tasks may require hours of hard work with the help of heavy duty shop equipment. Hence, references to lost time and down time are serious matters and not to be taken lightly.
It would be desirable for an electrolytic chamber to be rapidly serviceable, even when disassembly or replacement is required.
Further, it would be desirable for an electrocoagulation cell to be constructed in such a manner that clogging and corrosion are minimized.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the method and apparatus of this invention may comprise the following.